Process for the production of chlorine and aluminum chloride



Dec. 28 1926,

E. R. WOLCOTT PROCESS FOR THE PRODUCTION OF' CHLORINE AND ALUMINUM CHLORIDE Filed Feb. 28, 1921 Patented Dec. 28, 1926.

UNITED- STATE-sl PATENT oFFlcE.

EDSON WOLCOTT, 0F LOS ANGELES, CALJIOBNIA, ASSIGNOBTO THE TEXAS .COM-

PANY, OF NEW YORK, N. Y.,

a connonATIoN -or TEXAS.

PROCESS FOR THE PRODUCTIN 0F AND'ALLINUM CHLOBIDE.

applicati@ 'aleja sanitarias, i921.'- V serial No; nasca 1 This invention relates to ther-production' of aluminum chloride., and themam-object of the invention is to provide an economical;-

process for producing and regenerating chlorine in connection VWith' the production ride as hereinafter set forth involves as apreliminary stage the production of chlo rine, Which is preferably carried out in such `manner that 1t comprises two alternately conducted stages of operation; namely, a

chloridizing stage in which magnesium oxide, or other alkaline earth oxide, is subjected to the action of hydrochloric acid gas (hydrogen chloride) under suitable temper' ature conditions to produce a metallic chlo-v ride; and, an oxidizing stage, in which the chloride so produced is heated in the presence of oxygen-bearing gas (air or oxygen) v to produce metallic oxide, chlorin and water.

These operations may be carried out in a suitable retort, indicated at l, which may be of any suitable type, either vertical or horizoital, and is provided with suitable heating means (preferably by external heating) for maintaining` the retort at proper temperature for the reactions. Said retort is provided with inlet means 2 and 3 for supplying hydrochloricL acid gas and loxygenbearing gas, respectively, and with outlets 4 and 5 for discharge of residual gases in therespective .stages of the operation, it

being -understood that these inlets and outlets will be provided with suitable control means. Outlet 4 is opened in the chloridizing stage only and discharges into the atmos: phere. Outlet 5 is opened in the oxidizing stage only vand conducts the residual gases to suitable means, suchas afcompression plant 6, for compressing and coolingthegases'to cause sep'ara'tionofl lchlorine, which passes to suitable receiving means, suchvas a tanky the waste gasespassing off as indicated.

of an Oxy-chloride, the pro -f-'jprefer to use as a converting agent for .theproduction of vchlorine from hydrochloric acid, magnesium oxide, ora mixture or compound of magnesium oxide and niagnesium. chloride, such mixtureQin a suitable state-of division, being provided in the re` tort l and hydrochloric acid gas being supplied thereto through inlet 2 and the retort Vl being maintained at a suitable temperature,

for example, red heat, the magnesium compound is converted yvholly or partially to theform of magnesium chloride, the other product of the reaction being water (in the form of vapor) which psses olf at outlet t. The hydrochloric acid sup ly is then shut o' andair or oxygen, preiP andpre-heated, is supplied through pipe?,

v"and reacts with the magnesium chloride in the retortl to form Water and chlorine, the

-resultant'gases passing olf through the out- I vlet 5'of the retort to the means 5, 6 and 7 for separating and storing the chlorine. ln case air isv used as an oxidizing medium, in the above descrlbedoperation, the nitrogen present in the air serves'as a sweeping out gas for driving out the chlorine from the retort l as fast as it is produced, thereby acceleratin the reaction. In case pure oxygen is used, owever, as an oxidizing agent, it has the advantage of producing chlorine gas comparatively free from diluting gases, especially if the pgoportion of oxygen used is maintained onlyslightly in excess of the amount required tor the reaction taking place in the retort l; and the chlorinebeing in concentrated condition can-then be compressed directly to the form of liquidchlorine at minimum cost.

The production of erably pre-dried chlorine in the above described' manner by alternate chloridizavnial'ient'a'nd the operationmay be repeated indefinitely without a ecting the capacity of such agent forfurthe operation. It will be understood that, invgeneral, thematerial present in the retort 1 willbe in the nature rtions ofl oxygen and chlorine varying with the successive higher Atem erature.

stagesy of the operation, the amount of chlorine constituent increasing during the treatment With hydrochloric acid and the amount -of oxygen constituent increasing during the treatment with air or oxygen, but, in general, there will not be complete vconversion in either stage to the form of oxygen or chloride.

@ther metallic compounds maybe used in Ithe place of magnesium oxide in carrying out this process, thus, the oxide ot calcium, (or other alkaline earth) or the oxide of lead, or of copper may be used, or a mixture of the oxides or of the oxide and chloride of any of these metals.

rllhe above described process is particularly adapted for use in connection with the production of aluminum chloride for the reason that as preferably carried out it provides exit gases in addition to the chlorine which are available in the reactions taking place in the production ofaluminum chloride. ln such application of the invention it is desirableI to remove from the products of reaction in retort i1, during` the oxidizing stage, any excess or residual oxygen. For this purpose the gaseous products of reaction are led through a body of carbon in the same retort, or in another retort 8, producing carbon monoxide. The chlorine present may, if desired, be separated from such carbon monoxide by refrigeration or compression, or in any other suitable manner, or the mixture of chlorine and carbon monoxide may be used to produce carbonyl chloride, which may be utilized in the production of other chlorine products, or sold as such, being readily separable from the chlorine and other gasesv present by reason of its condensibility at a lower pressure or The gases passing from the ph crine roducing operation to a storage .tank land3 containing, lfor example, chlorine and carbon monoxide roduced as above described are passed (preflrably after thorough drying in a dryer 9 containing sulfuric acid, calcium chloride, or other drying agent) to a' retort 10 of an suitable construction, said retort being, or example, of either the horizontal or vertical type, and bein provided with means for external heating to maintain the contents of the retort at suitably high temperature, for example, about 900 C. Said retort contains oxygenbearing aluminum compound, for example, such as clay, or shale, together with carbon, which reacts with the chlorine and carbon monoxide supplied thereto to form aluminum chloride. The excess gases from the retort 10 are passed to a suitable condenser or collecting means 12 for condensing and removin therefrom the aluminum chloride produce In this operation any carbon monoxide supplied with thechlorinecon tributes'to the reaction taking place in the teiaeea retort 10, acting as avreducing agent for the oxygen-bearing aluminum compound present. The mixture of oxygen-bearing aluminuml` compound and carbon in the retort 10 aluminum compound and carbon may be produced by heating low grade coal, carbonaceous shale, oil shale, etc., in the' retort 10 to drive od volatileconstituents, such as hydrocarbons, and leave the residual carbon intimately mixed AWith aluminum silicate material. ln such a, case the preliminary distillation of the material to drive off volatile hydrocarbons may take place in a separate retort, o'r in the retort 10, in which the aluminum chloride is produced and volatilized, such volatile products being carried oli' or conducted away in such manner as not to pass through the aluminum collecting means 12 and being, if desired, collected and utilized in any suitable manner.

lt is desirable to carry out the aluminum chloride production and volatilization with a considerable excess of chlorine 4beyond that which is requirtfd for the reaction in order to insure sutliciently rapid volatilization of aluminum chloride and such excess of chlorine will be present in the residual gases after separation of the aluminum chloride therefrom; such residual gases may also con- -tain carbon monoxide and carbon dioxide produced in the reactions above referred to and more or less silicon tetrachloride. ln case there is any considerable `amount of silicontetrachloridc thus produced it is desirable to treat the same for recovery of chlorine therefrom, either in the form of free lchlorine, or hydrochloric a'cid. For the production of hydrochloric acid the residual gases may be led from' the separator 12 to a' spray chamber 14 into which Water is suplmll llU

plied by means 15, such Water reacting with the silicon tetrachloride to xform hydrated silica and hydrochloric acid. The liquid products of this reaction may pass into a separating chamber l16 which may be main-` ta1ned-at'such'temperature as to 'cause 16 may be treated with Water in an absorber 17 to form liquid hydrochloric acid and the resulting solution-may then-be heated in an gas with more or .less water vapor, the1 lat- .evaporator 18 to drive o hydrochloric acid y ter being removed` in dryer 19, if necessary, the dried hydrochloric acid gas being stored in a storage chamber 20 and either sold las a comnerclalproduct, or utilized as desired for the production'of chlorine, for example, by passing same through the inlet 2. When the gas is used in this manner as a chloridizing agent in retort 1, it needmot be dried. Itis not necessary in that case to ever remove the chlorine from the hydrochloric acid gas, and the gases may pass directly from the chamber 14 tothe retort l, it being understood that suitable pumping means are 'provided for forcing the gases back to such retort.

The gases passing from the absorber 17 may contain` the excess chlorine above referred to, together with carbon monoxide, and by passing such gases in contact with a mass of silica gel, or other absorbing agent, in a suitable container-"22 the chlorine may beabsorbed in such mass and subsequently liberated therefrom by heating, or otherwise, and thereby separated romv the carbon monoxide. The chlorine so produced substantially free from other substances may be conducted vto the retort 10, or to supply tank 13, torre-use, and the carbon monoxide so recovered from the apparatus 22 may be utilized in any suitable manner, for example, as fuel for one or more of the re- Y y, torting operations` above referredA to.

' with a catalgic body.

' TheA gas containing silicon tetrachlorid passing from the separator 12 may be treted for direct production of chlorine, for example, it` may be passed to a reaction chamher 24 to whlch air is supplied and which is maintained at suitable temperature to effect reaction between the silicon tetrachloride and the oxygen to produce silica and free chlorine, such chlorine being utilized in any suitable manner, for example, being passed back to the retort,- 10 aforesaid, and the silica being utilized or sold as a' commercial byproduct. Y

,An important feature of the above described method of chlorine production is that the treatment of the metallic oxide with h drogen chloride is substantially in the a sence of free oxygen, and, on the other hand, durillilg' the treatment of the resultin metallic c oride with oxygen, hydrogen c loride is substantially absent, thereby renderingthe operation more effective than when the two gases are brought concurrently in contact The temp atureof maintained in each of the stages of the proc'- ess at that point whichis most suitable for the special operation to be carried out, or

1 forthe production of the particular product -desired, for example, the temperature during the chloridizing) operation may be-maintained somewhata ove C. so that the water produced in thisoperation will be in the form ofsteam but the temperature will ever, both, stages of the operation may take.

place' at the same temperature, the retort i eing heated uniformly during both stages of the operation. o

Whilel an advantage of this process is that chlorine ma-y be produced in relatively pure and concentrated form, it may be so carried out that more orvless hydrochloric acid passes over withlthe chlorine, for example, if the chloridizing operation is so carried out that some water is retained by the charge in the retort 1, or if the oxygen-bearing gas contains some water, then hydrochloric acid will pass over along with the chlorine produced and in this way a mixed gas contain# ing chlorine and hydrochloric acid maybe produced, which is especially desirable' in some cases, for example, such a mixed gas may be used in the preliminary operation in the aluminum chloride producing retort to volatilize iron, or other impurities in the aluminum silicate` material. v to produce chlorine without admixture with hydrochloric acid,the charge in the retort 1 should be free from Water by heating lor otherwise and the oxygen-bearing gas should also be free from water, so as to prevent production of hydrochloric acid. Similarly, in the aluminum chloride 'producing operation, the charge in the retort 10 should be yfree from water and the chloridizing gases introduced thereinto should be free :fromI water so as to revent interference with the production o aluminum chloride by the presence of Water.

`What I claim is:

If itis desired l. The process which consists inpassing hydrochloric acid gas in contact with heated alkaline earth oxide to form the chloride thereof, then passing oxygen bearin gas in contact with the resulting metallic ch oride -to produce the oxide and free chlorine, an'

lli'n roduce l constituents and utilizing such hydrochloric acid, together with the oxide aforesaid, in cyclic operation of the process.

2. A process as set forth in claim 1 wherein treatment of the said remaining gas comprises contacting the same with water to iorm hydrochloric acid and hydrated silica and separating the hydrochloric acid and hydrated silica thus formed.

3. 'lhe `process of making aluminum chloride which consists in passing currents ot' hydrochloric acid gas and oxygen-containing gas into contact With a heated mass comprising an oxychloride of an alkaline earth metal, passing the resultant chlorine-containing gases into Contact with heated carbon to convert into carbon monoxid any oxygen contained in said gases and then bringing the oxygen-freed chlorine-containing gas into contact with argillaceous material and a reducing agent heated to produce vapors comprising aluminum chloride and silicon tetrachloride, separating the aluminum chloride 'from said vapors, treating the silicon tetrachloride to produce hydrochloric acid gas,

terasse and passing said gas` into contact with aforel said alkaline earth oxychloride.

4. The process of making aluminum chloridel which consists in passing currents of hydrochloric acid gas and oxygen-containing gas into contactl with a heated mass comprising an oxychloride of an alkaline earth metal, passing the resultant ohlorinefoontaining gases into contact with heated carbon to convert into carbon monoxid any oxygen contained in said gases and then bringing the oxygen-freed chlorine-containing gas into contact with argillaceous material and a reducing agent heated to produce vapors coinprising aluminum chloride and silicon tetrachloride, separating the aluminum chloride from said vapors, hydrolyzing said silicon tetrachloride to produce hydrochloric acid gas and passing said gas into contact with aforesaid mass of oxychloride.

lu testimony whereof l have hereunto subscribed my name this 17th day of February, 1921.

nnsoN n. Woiioorr. 

